This script can be executed using the "Code by Zapier" app to get an image from a page - https://zapier.com/zapbook/code/

zapier_get_thumbnail_image_from_html.js

/*
  You need to set an inputData param called 'link'
  with the URL field you want to parse.
  More info: https://zapier.com/help/code/#data-variables
*/
fetch(inputData.link)
  .then(function(res) {
    return res.text();
  })
  .then(function(body) {
    var match = /<meta property=['"]og:image['"] content=['"](.*)['"] \/>/.exec(body);
    var image = null;

    image = match? match[1]: null;

    if(!image){
      match = /<link href=['"](.*)['"] rel=['"]image_src['"]\/>/.exec(body);
      image = match? match[1]: null;
    }

    if(!image){
      match = /<img src=['"](.*)['"] (.*)\>/.exec(body);
      image = match? match[1]: null;
    }

    if(!image){
      console.log("No image available");
      image = 'http://geodevelopers.org/images/no-image.png';
    }else{
      if(image[0] === "/"){
        var arr = inputData.link.split("/");
        arr.splice(3);
        image = arr.join("/") + image;
      }
      console.log(image);
    }       
      
    var output = {image: image, rawHTML: body};
    callback(null, output);
  })
  .catch(callback);